Enable slimming paint for fast/repaint

LayoutTests/platform/mac/fast/repaint/line-flow-with-floats-3-expected.txt

 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "repaintRects": [
         [372, 371, 48, 80],
         [369, 368, 32, 18],
         [356, 389, 64, 80],
         [354, 422, 15, 54],
         [65, 386, 303, 36],
         [65, 368, 356, 54],
         [14, 422, 72, 18],
         [14, 404, 355, 36],
         [8, 368, 418, 198]
+      ],
+      "paintInvalidationClients": [
+        "InlineTextBox 'The players all played at once without waiting'",
+        "RootInlineBox",
+        "InlineTextBox 'for turns,\n'",
+        "InlineTextBox 'quarrelling all the while, and fighting'",
+        "RootInlineBox",
+        "InlineTextBox 'for the hedgehogs; and in\n'",
+        "InlineTextBox 'a very short time '",
+        "InlineTextBox 'the'",
+        "RootInlineBox",
+        "InlineTextBox 'Queen'",
+        "InlineTextBox ' was in a furious passion, and went\n'",
+        "InlineTextBox 'stamping'",
+        "RootInlineBox",
+        "InlineTextBox 'about, and shouting \u2018Off with his head!\u2019 or \u2018Off with'",
+        "RootInlineBox",
+        "InlineTextBox 'her head!\u2019 about once in a minute.\n'",
+        "RootInlineBox",
+        "InlineTextBox 'Alice began to feel very uneasy: to be sure, she had not as\n'",
+        "InlineTextBox 'yet'",
+        "RootInlineBox",
+        "InlineTextBox 'had any dispute with the Queen, but she knew that it might'",
+        "RootInlineBox",
+        "InlineTextBox 'happen any minute, \u2018and then,\u2019 thought she, \u2018what would'",
+        "RootInlineBox",
+        "InlineTextBox 'become of\n'",
+        "InlineTextBox 'me? They\u2019re dreadfully fond of beheading people'",
+        "RootInlineBox",
+        "InlineTextBox 'here; the great\n'",
+        "InlineTextBox 'wonder is, that there\u2018s any one left alive!\u2019'",
+        "RootInlineBox",
+        "LayoutBlockFlow P",
+        "LayoutText #text",
+        "InlineTextBox 'The players all played at once without waiting\n'",
+        "LayoutBlockFlow (floating) SPAN id='greenFloat'",
+        "LayoutText #text",
+        "InlineTextBox 'for'",
+        "InlineTextBox 'turns,\n'",
+        "InlineTextBox 'quarrelling all the while, and fighting'",
+        "InlineTextBox 'for the hedgehogs; and in\n'",
+        "InlineTextBox 'a very short time'",
+        "LayoutText #text",
+        "InlineTextBox 'the Queen'",
+        "LayoutText #text",
+        "InlineTextBox ' was in a furious passion, and went'",
+        "InlineTextBox 'stamping about, and shouting \u2018Off with his head!\u2019 or'",
+        "InlineTextBox '\u2018Off with\n'",
+        "InlineTextBox 'her head!\u2019 about once in a minute.\n'"
       ]
     }
   ]
 }